Marriages seem to succeed or fail based on an understanding of how partners balance out each other. The statement the opposites attract is not right, but it is not really wrong either. Couples seem to need their partners to have traits that they themselves don’t possess. But they can’t be true opposites. Core Values should be more or less the same. Life goals need to be achievable for both. Where you might find opposites would be in something like talkative and quiet. One partner might be carefree and the other disciplined. One might be a risk taker and the other risk adverse. If you think about how it would be to marry someone just like you I suspect you quickly determine that is would not be good at all.
Why do we need a counter balance. We all have traits that can be a bit extreme. In some situations life calls for the extreme, but it is rare. If our partner can keep us from going to far then we benefit. But what I often find is that the partner resents being counter balanced. This fact can lead to one of the most significant cause of marital strife. Simple put the Hunter needs to marry the Gatherer and vice versa. The Hunter being told to stay home because the home has enough meet can keep the Hunter from risking his/her health needlessly. But the Hunter being told to stay is often like a dog being told not to eat the food in the bowl. The urge to Hunt can be so strong the resentment can build. In the modern marriage we need to accept that as annoying as it may be to be pulled away from our more extreme traits it is necessary for overall life success.